Device for implanting a prosthesis for a heart valve and assembly procedure

ABSTRACT

A device for implanting a heart prosthesis including a central body, a containment portion having one or more sub-components, and a release device for the central body capable of being inserted into a catheter. A device for assisting the connection operation between the central body and the sub-components of the containment portion includes an assembly of catheters, of which there are at least two catheters for each sub-component of the containment portion, the catheters being joined to each other over a portion thereof and having at least one free end for each catheter.

CROSS REFERENCE TO RELATED APPLICATION

This is a divisional of prior U.S. Ser. No. 16/522,164, filed Jul. 25,2019, the disclosure of which is hereby incorporated by reference in itsentirety.

FIELD OF THE INVENTION

The present invention relates to a device for implanting a prosthesisfor a heart valve and an assembly procedure.

The invention has been developed with particular regard, though in anon-limiting manner, for a device for use during a procedure forimplanting a heart prosthesis for replacing the physiological functionof a malfunctioning heart valve and in particular a heart prosthesis foran atrio-ventricular heart valve.

Technological Background

Heart valves are complex and delicate organs which govern the correctfunction of the human heart. The main objective thereof is to make theblood flow inside the cardiac cavities unidirectional, being essentialboth in the filling phase of the cavity, the diastolic phase, and in thedischarge phase of the blood, the systolic phase.

In order to optimize the efficiency of the pumping action of the blood,the heart is structured in two different compartments, right and left,respectively, each of which is in turn subdivided into two chambers, theatrium and ventricle, respectively. The right compartment of the heart,which is composed by the right atrium and ventricle, returns the bloodfrom the peripheral circulation and directs it towards the pulmonarycirculation for oxygenation thereof. The left compartment, which issimilarly subdivided into left atrium and ventricle, supplies theperipheral vascularization, returning the oxygenated blood frompulmonary circulation and pumping it towards the systemic circulation.

In order to make the blood flow unidirectional inside the heart, a valveis positioned at the outlet of each chamber. The valves which arepositioned at the outlet of the atria are the atrio-ventricular valvesbecause they connect the atrial chamber to the ventricular chamber ofeach side of the heart. At the right side of the heart, this valve isalso referred to as the tricuspid valve, at the left side it is usuallyindicated as the mitral valve. Finally, the valve which is positioned atthe outlet from the right ventricle is called the pulmonary valve whilethe valve at the outlet from the left ventricle is called the aorticvalve.

Pathologies which affect the function of a heart valve are among themost serious in the cardiovascular field. Among these, the insufficiencyof the mitral valve, that is to say, the incapacity thereof to closecompletely, is a valve pathology which is highly impairing because itreduces the efficiency of the pumping action at the left side of theheart, which is responsible for blood circulation for the entire body.

In the current prior art, the standard therapy for treating severe valvemalfunctions is the replacement of the valve with an implantableprosthesis. In other cases, mainly in the case of malfunctions of themitral valve, there is provision for the repair thereof. In both cases,it is provided via an open-heart surgical procedure which affords directaccess to the malfunctioning valve. This procedure requires thetemporary arrest of the heart and the creation, by means of suitablepumps and oxygen exchangers, of an extracorporeal artificial bloodcirculation. Notwithstanding the refinement of the techniques formanaging the cardiac arrest and improving the extracorporeal circulationsystems, the therapy in open heart conditions presents risks as a resultof the invasive nature thereof and the duration of the procedure. Infact, the implantable prostheses, both for repairs and for replacements,commonly used during the conventional surgery usually require a longoperation for fixing at the location of the implantation by means ofspecific suture techniques. In some cases, it is not even possible tointervene surgically as a result of the general conditions of thepatient, for example, due to advanced age or the presence of concomitantpathologies.

In order to overcome these limitations, there have recently beendeveloped procedures with interventions of reduced invasiveness,so-called transcatheter procedures. To this end, radially collapsibleprostheses which can self-anchor at the implantation site are used. Theprostheses can be implanted by means of catheters which are capable ofnavigating inside the vascular system and releasing the heart prosthesisby reaching the implantation site from a remote access created, forexample, in a peripheral vessel, such as a femoral vein or artery. Thevalve malfunctions can thus be corrected with a beating heart and withlimited use of surgical practices. In the current state, transcathetertechniques are clinical standard of care only for treating the aorticvalve.

The situation is different with regard to the treatment of malfunctionsof the atrio-ventricular valves, in particular the treatment of mitralinsufficiency. The complex anatomical configuration of the valve and ofthe structures which surround it, the variability of the pathologies,also very different from each other, which affect the valve directly orindirectly, make it extremely difficult to comply with the requirementsfor a reliable and effective implantation in a mitral valve via thetranscatheter route.

In the variety of single designs developed, the main technologiesdeveloped for transcatheter prostheses for atrio-ventricular valvesprovide for apical access to the heart. The procedure requires athoracic incision in order to expose the apex of the left ventricle.Subsequently, the cardiac apex is punctured in order to be able toinsert an apical port. Via the apical port, the catheters necessary tocomplete the procedure are inserted successively.

A problem of this approach is that it brings about damage to the heartin a rather delicate portion, such as the apex, with consequences thatcan be detrimental to the patient, such as bleeding, aneurisms, etc.

Statement of the Invention

An object of the invention is to solve the problems of the prior art andin particular to provide a procedure for implanting a heart prosthesiswhich is transcatheter and which does not damage the apex of the heart.Another object is to provide a procedure which is even safer for thepatient. In particular, an object is to provide a guidewire introducerdevice and a device for implanting a heart prosthesis which are reliableduring use and safe in order to allow such a procedure to be carriedout. Another object is to provide a procedure for assembling a heartprosthesis using such a device for implantation.

An embodiment relates to a guidewire introducer device and a device forimplanting a heart prosthesis which are developed specifically forallowing a transcatheter implantation procedure with transseptal access.With transseptal access it is intended to be understood an access to themitral valve which, starting from a peripheral femoral vein, navigatesin the inferior vena cava up to the right atrium and finally arrives atthe left atrium through an aperture which is created, withinterventional methods, in the septum between the two atria. The leftatrium affords anterograde access to the mitral valve to be treated. Inthis manner, damage, that is to say perforation, of the left ventriclewhich is associated with the transapical procedure, that provides accessto the mitral valve from the ventricular side, that is to sayretrograde, is prevented.

According to a first aspect, there is described herein a guidewireintroducer device for positioning at least one guidewire around a heartvalve. The device may be capable of deploying guidewires throughtransseptal access. The device may comprise a first catheter which maybe provided with at least one distal deflection system. The device maycomprise a second catheter which may be inserted inside the firstcatheter. The second catheter may comprise a lumen which is suitable forhaving a guidewire sliding therein. The second catheter may be providedwith a distal deflection system for deflecting the end thereof,preferably through an angle greater than 90° in order to allow the zoneimmediately under the leaflets of the native valve to be best reached.The device may comprise a third catheter. The third catheter may beinserted inside the first catheter. The third catheter may have thereina device for capturing the guidewires. The third catheter may beprovided with a distal deflection system. The deflection system of thesecond catheter may comprise a wire.

According to another aspect, there is described herein a guidewireintroducer device for deploying at least two guidewires around a heartvalve. The second catheter may comprise two lumens which are suitablefor having guidewires sliding therein. The two lumens may terminate soas to face in substantially mutually opposite directions.

According to an advantageous aspect, a guidewire introducer devicecomprises a second catheter. The guidewire introducer device is providedwith a radiopaque and/or echo-opaque element. The radiopaque/echo-opaqueelement may be positioned on a distal tip of the second catheter,preferably embedded therein.

According to another aspect, a guidewire introducer device may comprisea first catheter with a single lumen.

According to another aspect, there is described herein a procedure forpositioning at least one guidewire around a heart valve; the proceduremay comprise the step of providing access for a first catheter through avein, preferably the femoral vein. The first catheter may be introducedinside the right atrium, through the inferior vena cava IVC. There maybe produced a puncture in the septum between the two atria in order toaccess the left atrium. The procedure may comprise the step of insertinga guidewire introducer device in the left ventricle, passing though themitral valve, and deploying one or more guidewires around the nativevalve.

According to a preferred aspect, there is described herein a procedurefor positioning at least one guidewire around a heart valve, theprocedure comprising the steps of:

-   -   providing access for a first catheter through a vein,    -   inserting the first catheter inside the right atrium, through        the inferior vena cava and entering the left atrium through a        puncture of the septum between the two atria,    -   inserting a guidewire introducer device into the left ventricle,        passing through the mitral valve, and positioning one or more        guidewires around the native valve.

According to another aspect, there is described herein a device forimplanting a heart prosthesis. The heart prosthesis may comprise acentral body and a containment portion. The containment portion may besubdivided into one or more sub-components. The device for implanting aheart prosthesis may comprise a release device for the central body. Therelease device may be capable of being inserted into a catheter. Thedevice for implanting a heart prosthesis may comprise a device forassisting the connection operation between the central body and thesub-components of the containment portion. The device for assisting theconnection operation between the central body and the sub-components ofthe containment portion may comprise an assembly of catheters. There maybe at least two catheters for each sub-component of the containmentportion. The catheters may be joined to each other via a portion thereofand may each have at least one free end. The catheters may be groupedtogether in the same sheath. The sheath may group together the cathetersalong a portion thereof. The sheath may leave free at least one end foreach catheter. The sheath may further comprise an additional lumen for aguidewire, preferably a central one. Advantageously, the catheters whichconstitute the assembly of catheters may be steadily joined to eachother.

According to another aspect, a device for assisting the connectionoperation between the central body and the sub-components of thecontainment portion may comprise an assembly of catheters which areincompressible in a longitudinal direction. In this manner, during use,they form an incompressible abutment channel for a guidewire.Preferably, the catheters which constitute the assembly of catheters maybe flexible.

According to another aspect, there is described herein a procedure forassembling a heart prosthesis. The heart prosthesis may comprise acentral body and a containment portion. The containment portion may besubdivided into one or more sub-components. The procedure described maycomprise the step of inserting a guidewire into each sub-component ofthe containment portion. It may comprise the step of sliding thesub-components in such a manner that both the ends of the guidewire areoutside the sub-component itself. The procedure may comprise the step ofinserting, for each sub-component of the containment portion, each endof the guidewire in a corresponding connecting element, for theconnection of the central body and the containment portion. Theprocedure may comprise the step of inserting each end of the guidewireinto a corresponding catheter of the assembly of catheters. It maycomprise the step of drawing the ends of each guidewire in order toconnect the central body and the sub-components of the containmentportion.

According to another aspect, there is also described herein a procedurefor implanting a heart prosthesis. The heart prosthesis may comprise acentral body and a containment portion, which is sub-divided into one ormore sub-components. The procedure may comprise the step of affordingaccess for a first catheter through a vein. Preferably, the access maybe afforded in the femoral vein. The procedure may comprise the step ofinserting the first catheter through the inferior vena cava IVC. Thefirst catheter may be inserted up to inside the right atrium. There maybe created a puncture in the septum between the two atria. Through thispuncture, it is possible to access the left atrium. The procedure maycomprise the step of providing one or more guidewires around the nativevalve; this operation may be carried out by means of a guidewireintroducer device. It is possible to insert the sub-components of thecontainment portion. The procedure may comprise the step of inserting adevice for implanting a heart prosthesis. It is then possible to connectthe central body to the sub-components 22 of the containment portion 18.The release in position of the central body may be brought about bypushing the central body out of the device for implantation.

According to another aspect, the procedure for implanting a heartprosthesis provides for the step of inserting each sub-component intothe heart by guiding it with at least one guidewire which is arrangedaround the native valve, preferably sliding each sub-component over theat least one guidewire (over the wire).

According to another aspect, the procedure for implanting a heartprosthesis may provide for using a device for implanting a heartprosthesis comprising a device for assisting the operation of connectingthe central body and the sub-components of the containment portion whichmay comprise an assembly of catheters; the procedure may comprise thesteps of inserting each end of the guidewire into a correspondingconnecting element for the connection of the central body and thecontainment portion and inserting each end of the guidewire into acorresponding catheter of the assembly of catheters, in the free endthereof. The procedure may further comprise the step of acting on theends of the guidewire in order to establish the connection between thecentral body and the sub-component of the containment portion.

According to another aspect, there is described herein a procedure forimplanting a heart prosthesis comprising a central body for prostheticleaflets and a containment portion which is subdivided into one or moresub-components, the procedure comprising the steps of:

-   -   providing access for a first catheter through a vein,    -   inserting the first catheter inside the right atrium, though the        inferior vena cava and accessing the left atrium through a        puncture of the septum,    -   providing one or more guidewires around the native valve,    -   inserting the sub-components of the containment portion,    -   inserting a device for implantation of a heart prosthesis,    -   connecting the central body to the sub-components of the        containment portion, and    -   pushing the central body until it is caused to be released in        position.

There is further described herein a procedure for implanting a heartprosthesis, in which each sub-component is inserted by sliding it overone of the guidewires which are arranged around the native valve.

Advantageously, a procedure for implanting a heart prosthesis uses adevice for implanting a heart prosthesis with all or some of theabove-described features; according to the procedure, after insertingthe sub-components, for each sub-component of the containment portionthere are carried out the steps of:

-   -   inserting each end of the guidewire into a corresponding        connecting element, for the connection of the central body and        the containment portion,    -   inserting each end of the guidewire in a corresponding catheter        of the assembly of catheters, at the free end thereof, and    -   tensioning the ends of the guidewire, bringing about the        connection between the central body and the sub-component of the        containment portion. Preferably, the access is brought about by        means of a femoral vein.

BRIEF DESCRIPTION OF THE DRAWINGS

The solution according to one or more embodiments of the invention, aswell as additional characteristics and the relative advantages, will bebetter understood with reference to the following detailed descriptionwhich is given purely by way of non-limiting example and which isintended to be read with the appended Figures, in which for simplicitycorresponding elements are referred to with identical or similarreference numerals and the explanation thereof is not repeated. In thisregard, it may be expressly understood that the Figures are notnecessarily to scale, with some details which may be exaggerated and/orsimplified and that, unless indicated otherwise, they are simply used toconceptually illustrate the structures and the procedures described.

In particular:

FIG. 1 is a general schematic illustration of a heart prosthesis fortreating heart valves, in accordance with an embodiment of theinvention.

FIG. 2 shows the heart prosthesis of FIG. 1 in a disassembled state.

FIG. 3 shows a step of the procedure for implanting the heartprosthesis, in which access is afforded by means of the interatrialseptum.

FIG. 4 shows a detail of the second catheter of the guidewire introducerdevice.

FIG. 5 is a different view of the same detail as FIG. 4 .

FIG. 5 a shows a variant of the second catheter of the guidewireintroducer device.

FIG. 6 shows a step of the procedure for implanting the heartprosthesis, in which the second catheter of the guidewire introducerdevice is caused to advance in the direction of the mitral valve.

FIG. 7 shows a step of the procedure for implanting the heartprosthesis, in which the second catheter of the guidewire introducerdevice is caused to advance in the left ventricle through the mitralvalve.

FIG. 8 shows the step of FIG. 7 in a close-up view.

FIG. 9 shows a step of the procedure for implanting the heartprosthesis, in which a capture device for guidewires is positioned.

FIG. 10 shows a step of the procedure for implanting the heartprosthesis, in which a first guidewire is positioned.

FIG. 11 shows a step of the procedure for implanting the heartprosthesis, in which the positioning of the first guidewire iscompleted.

FIG. 12 shows a step of the procedure for implanting the heartprosthesis, in which the sub-components of the containment portion ofthe heart prosthesis are inserted.

FIG. 13 shows a step of the procedure for implanting the heartprosthesis, in which a device for implanting a heart prosthesis isinserted.

FIG. 14 is a view of a device for assisting the connection operationbetween the central body and the sub-components of the containmentportion.

FIG. 15 is a cross-section of the device of FIG. 14 .

FIG. 16 shows a step of the procedure for implanting the heartprosthesis, in which the central body is advanced.

FIG. 17 shows a step of the procedure for implanting the heartprosthesis, in which the central body and the sub-components of thecontainment portion are connected.

FIG. 18 shows a step of the procedure for implanting the heartprosthesis, in which the device for assisting is removed.

FIG. 19 shows the heart prosthesis in a configuration ready for releasein situ.

FIG. 20 shows the heart prosthesis ready for release in situ,illustrated in the heart.

FIG. 21 shows the heart prosthesis in a correctly positioned state.

FIG. 22 is a cross-section of a variant of the second and thirdcatheters of the guidewire introducer device.

FIGS. 23 to 26 show another variant of the second and third catheters ofthe guidewire introducer device.

DETAILED DESCRIPTION

Now with reference to the drawings, in FIGS. 1 and 2 there is describedan implantable heart prosthesis 10 which is used to replace thefunctionality of an atrio-ventricular valve.

The heart prosthesis 10 comprises a prosthetic structure 12 for supportand interfacing with the native valve and by a group of flexibleprosthetic leaflets 14 which are fixed therein. The prosthetic structure12 comprises in particular:

-   -   a central body 16,    -   a containment portion 18, and    -   connecting elements 20 for connecting the central body 16 and        the containment portion 18.

The prosthetic structure 12, as for each of the elements thereof, isconfigured so as to be collapsible without any consequence for thesafety and the functionality of the heart prosthesis. Therefore, it ispossible to temporarily reduce the radial dimensions of the prosthesisin order to allow the introduction thereof inside the cardiac cavitiesthrough access ports which have a reduced aperture and which arecompatible with the techniques of minimal invasive surgery, and inparticular with the techniques of transcatheter positioning and heartprosthesis implantation according to the present invention. In otherwords, it is possible to insert the heart prosthesis 10 inside acatheter with a small radial profile, which is capable of conveying theprosthesis inside the heart cavity, near the implantation site, througha minimal invasive access, and there to carry out the deployment and theimplantation thereof, functionally replacing the native valve.

There are described in detail herein below the different portions intowhich the prosthetic structure 12 is divided.

The central body 16 is the portion of the prosthetic structure 12 whichdelimits the conduit for the passage of blood through the device. Thereare fixed inside the central body 16 the flexible prosthetic leaflets 14which make the blood flow unidirectional inside the conduit, as known,for example, from the Italian patent No. 0001422040 by the sameApplicant.

The central body 16 is a radially collapsible resilient structure whichtends, as a result of resilient return, also to expand to a diametergreater than the maximum diameter which maintains coaptation, that is tosay, the contact, between the free edges of the closed prostheticleaflets 14.

The containment portion 18 is the portion of the prosthetic structurewhich counteracts and limits the free expansion of the central body 16,preventing it from exceeding the maximum diameter which is compatiblewith the preservation of coaptation between the prosthetic leaflets 14.The containment portion 18 has a substantially annular geometry and islongitudinally inextensible, that is to say, it does not modifysignificantly the peripheral extent thereof even when the central body16 expands inside it while applying a radial force outward.

The containment portion 18 is preferably subdivided into twosub-components 22 which are separated from each other, substantially inthe form of an arc; for simplicity, the two sub-components will beindicated below by the term “arcs”. Each arc 22 can be selectivelyengaged with the connecting elements 20, with which it is steadilyjoined in the final implantation configuration.

Each end 24 of each sub-component 22 is equipped with an engagementportion 26, preferably capable of assuming orientations outside theannular plane. In the embodiment depicted, the engagement portion 26 isorientated substantially perpendicularly to the plane of the annulus. Inturn, the connecting elements 20 are equipped with pins 28 which aresuitable for being received in axial holes 27 which are present in theengagement portions 26. A pair of pins 28 is present on each of the twoconnecting elements 20, arranged substantially in angular positionswhich are diametrically opposed with respect to the central body 16.These pins 28, as well as the engagement portions 26 which are presentat the ends of the arcs 22 of the containment portion 18, can beprovided with barbs or lips or other surface discontinuities which areintended to create mechanical interference between the portions and/orto increase the friction in the pin/hole connection, improving thestability of the connection between the sub-components 22 of thecontainment portion 18 and the connecting elements 20. The pins 28 areorientated in a coherent manner relative to the orientation of theengagement portions 26 which are present on the sub-components 22 of thecontainment portion 18, so that the pin/hole connection maintains thecontainment portion in a geometrically consistent plane with the annulusof the native valve. Furthermore, the pins 28 are pierced axially inorder to allow the passage of a guidewire, as better described below.

It is evident that the pin/hole connection mechanism could insteadcomprise a pin at the end of the sub-components 22 and a cylindricalhole in the connecting elements 20. More generally, the pin/holeconnection has a purely exemplary purpose, without any limitingintention of the generality of the solution.

Naturally, the prosthesis may also comprise a different number ofsub-components 22. For example, it may comprise a single sub-componentand therefore be formed in the manner of an open ring. The versiondescribed with two sub-components 22 is the preferred one, however,because it allows the use of two guidewires which, as a result of theintroducing device for guidewires described below, are easier toposition correctly than a single guidewire which could remain entangledin the chordae tendineae. However, a third sub-component does notsimplify the positioning operations and therefore is substantiallyunnecessary, but should not be excluded.

In use, the leaflets of the native valve remain entrapped inside thecoupling between the central body 16 and the containment portion 18.Furthermore, the containment portion 18 also has the function ofstabilizing the native valve annulus, preventing the radial forceapplied by the central body 16, while being necessary to ensureeffective anchoring of the prosthesis, from being transferred to thesurrounding anatomical structure which is usually affected bydegenerative and dilating processes which are associated with thepathology which makes the atrio-ventricular valve malfunction.

For clarity reasons, in the drawings of FIGS. 1 and 2 , as for in theFigures which follow, the external diameter of the central body 16 isillustrated having dimensions less than the internal dimensions of thecontainment portion 18. In other words, the Figures show these twocomponents of the prosthetic structure 12 not in contact with each otherin the configuration of full expansion. In reality, it is possible tohave over-dimensioning of the central body 16 with respect to thedimensions of the containment portion 18. In this case, there is aninterference between the two portions of the prosthetic structure 12 andeffectively the central body 16 applies a radial pressure to thecontainment portion 18 when the latter carries out its constrainingaction with respect to the expansion, independently of the thickness ofthe tissue which remains captured in between the two portions of theprosthetic structure 12. This radial pressure increases the stability ofthe anchorage to the native valve leaflets.

There will now be described a preferred procedure for implantation ofthe heart prosthesis 10 described above.

Initially, there is afforded access through the femoral vein or theiliac vein. Where possible, the access from the femoral vein ispreferred because it is significantly simpler and more direct. Inparticular, it doesn't require an invasive surgical procedure. Anintroducer catheter may be used with the main objective of protectingthe femoral vein which has a small calibre.

The introducer catheter, when present, is positioned through the femoralvein in order to create the access to a vessel having a larger diameter.There is then inserted a main catheter 32 which slides inside theintroducer catheter, when provided, through the inferior vena cava IVCup to the right atrium, as can be seen in FIG. 3 .

The main catheter 32 is provided with a distal deflection system so thatthe end 34 thereof can be bent by the operator in the direction of theleft atrium. A puncture in the septum S between the two atria is thenperformed, allowing access to the left atrium. Inside the main catheter32, a guidewire introducer device 36 is inserted.

As mentioned above, it is not mandatory to provide an introducercatheter but instead there may be used directly a main catheter 32 whichgains access to the right atrium through the inferior vena cava.Furthermore, the main catheter may also be inserted up to a locationinside the left atrium; it thereby allows the insertion of the guidewireintroducer device 36 directly in the left atrium.

The guidewire introducer device 36 is a device the function of which isto allow the deployment around the leaflets of the native mitral valve Vof guidewires which are necessary for the subsequent positioning of theheart prosthesis 10.

The guidewire introducer device 36 comprises a first catheter 40, insidewhich a second catheter 44 and a third catheter 45 slide. The firstcatheter 40 is a single-lumen catheter. It is provided with a distaldeflection system so that the end 42 thereof can be orientated by theoperator in the direction of the mitral valve V.

The second catheter 44, which can better be seen in the detailed FIGS. 4and 5 , comprises two lumens 46 and 48 which are suitable for havingguidewires sliding therein. The two lumens are arranged parallel witheach other and beside each other over a greater portion of the secondcatheter 44. In the end 50 of the second catheter 44, the two lumenscurve through an angle of approximately 90° in substantially oppositedirections. The two lumens 46 and 48 therefore terminate not at a distaltip 51 of the catheter 44, but instead at the side thereof indiametrically opposed positions in respective holes 41 and 43. In otherwords, two guidewires inserted in the lumens 46 and 48 exit from thesecond catheter 44 oriented in diametrically opposed directions.

The second catheter 44 further comprises a deflection system. Thedeflection system according to the exemplary embodiment depictedcomprises a wire 52. The wire 52 is fixed to the end 50 of the catheter,runs externally from the catheter over a short portion and then insidethe catheter. The operator may pull the wire 52 in order to establish acurvature, which can be very pronounced, for the second catheter 44, ascan clearly be seen in FIG. 4 . The curvature is greater than 90°.However, it is not impossible to use other deflection systems. Forexample, inside the second catheter there may be incorporated a segmentof a shape-memory material so that it can be inserted in a stretchedstate in the first catheter 40 and recovers the correct curvature whenit is pushed out of the first catheter 40. An example of such aconfiguration is shown in FIG. 5 a , in which a wire 152 of shape-memorymaterial, for example, of titanium nickel alloy (Nitinol) isincorporated inside the second catheter 144.

There is provided at the distal tip 51 a segment 53 of radiopaque orecho-opaque material. The segment 53 is embedded inside the distal tip51 which is preferably rounded in order to prevent accidental lesions.

The third catheter 45, as better described below, is also insertedinside the first catheter 40 and receives therein a guidewire capturingdevice 47 (a snaring device), as better described below. It may be notedthat the guidewire capturing device which is depicted, comprisingdifferent collapsible rings or loops grouped together, is one of themany possible capturing devices which can be used that has been found tobe particularly effective for the specific application. However,different capturing devices are not excluded, for example, having asingle loop or a different number from the one of the device depicted.

Now turning to the procedure for implanting the heart prosthesis, theguidewire introducer device 36 which has been inserted inside the maincatheter 32 is advanced inside the left atrium (FIG. 3 ), through theseptum S. It may be noted that the end 34 of the main catheter 32 may belocated in the right atrium, as in the Figure, or in the left atrium.The end 42 of the first catheter 40 of the guidewire introducer device36 is bent so that it points towards the valve V, therefore towards thebottom in FIG. 6 .

The second catheter 44 of the guidewire introducer device 36 is made toslide inside the first catheter 40 of the guidewire introducer device 36(FIG. 6 ); the end 50 exits and takes on a pronounced curvature which isdirected in the opposite direction to the curvature of the end 42 of thefirst catheter 40. The second catheter 44 is in fact bent upwards inFIG. 6 .

The guidewire introducer device 36 is advanced further (FIG. 7 ) insidethe main catheter 32 and the second catheter 44 is pushed into the leftventricle, through the valve V.

Once the second catheter 44 of the guidewire introducer device 36 isinside the left ventricle, it is slightly retracted so that the distaltip 51 thereof is positioned behind the posterior leaflet of the nativevalve. In particular, the distal tip 51 is preferably positioned behindthe central segment (scallop) which is normally designated as P2. Tothis end, the presence of the segment 53 of radiopaque material at thedistal tip 51 is particularly advantageous. In case of doubts concerningthe exact positioning or the orientation of the end 50 of the catheter,it is in fact possible to verify it directly with an ultrasound probe orby means of fluoroscopy. The segment 53 of radiopaque material is to beoriented in a direction tangent to the edge of the valve.

FIG. 8 shows a detailed schematic view of the left ventricle, in whichthe native mitral valve V is clearly visible, with the two bundles ofchordae tendineae T, as well as the aortic valve A. The end 50 of thesecond catheter 44 of the guidewire introducer device 36 is depicted inthe correctly positioned state behind the posterior leaflet of thenative valve V. It may be noted that the catheter 44 does not cross thebundles of chordae tendineae.

Now with reference to FIG. 9 , the third catheter 45, with the guidewirecapturing device 47 therein, is slided inside the first catheter 40until it is introduced inside the left ventricle. The second catheteralso has, near the end 54 thereof, a deflection system 56. Thisdeflection system may be generally identical to the wire 52 describedabove with reference to the second catheter 44. According to a preferredvariant, however, it is made for constructional simplicity with a wirewhich slides inside the wall of the catheter; a flexible metal structurewith a rigid backbone embedded in the thickness of the catheter producesthe effect of the curvature. Other known mechanisms in the prior artshould not be excluded, however. Furthermore, the guidewire capturingdevice 47 is inserted in a covering sheath 55.

The third catheter 45 is orientated with the end 54 curved in anopposite direction with respect to the direction in which the end 50 ofthe second catheter is curved, therefore in the direction of the aorticvalve. The guidewire capturing device 47 is pushed out of the respectivethird catheter 45 and out of the sheath 55 until it is positioned in theLVOT (left ventricular outflow tract), that is to say in front of theaortic valve.

By maintaining the guidewire capturing device 47 in this position, afirst guidewire 56 is inserted in the first lumen 46 of the secondcatheter of the guidewire introducer device 36. The end 57 of theguidewire 56 is pushed (FIG. 10 ) into the ventricle by the operator. Asa result of the effect of the precise positioning of the distal tip 51of the second catheter 44, of the lateral position of the outlet 41 ofthe lumen 46, of the heart configuration, and of the blood stream thatduring systole is naturally directed towards the aortic valve A, the end57 of the guidewire 56 is driven around the valve and in the directionof the LVOT. Once the LVOT has been reached, it is captured by theguidewire capturing device 47 which has already been positionedbeforehand. Subsequently, the retrieval of the end 57 of the guidewire56 is carried out, by withdrawing the third catheter 45.

Alternatively, it is also possible to position the guidewire capturingdevice 47 inside the aorta, that is to say beyond the aortic valve A.The guidewire will be pushed into the aorta by the blood flow and thecapture operation may therefore be carried out.

Once the end 57 of the guidewire 56 has been captured, the guidewire 56forms a half-loop around the valve V (FIG. 11 ).

In a generally symmetrical manner, it is carried out the formation of asimilar half-loop around the valve V with a second guidewire 58 that isinserted into the second lumen 48 of the second catheter 44. In thismanner, the valve V is completely surrounded by the two guidewires 56and 58, which are correctly positioned. To this end, it is possible touse the same guidewire capturing device 47 which is used to capture thefirst wire or, preferably, another guidewire capturing device 47 whichis also received in the third catheter 45. In this case, the thirdcatheter 45 preferably has a double lumen.

Naturally, it is also possible to use a guidewire positioning devicewhich is similar to the one described above in detail in order toposition a single guidewire which carries out the complete loop aroundthe native valve. In this case, however, the guidewire positioningprocedure becomes more complex: although there are fewer steps necessary(it is not necessary to repeat the steps for the second wire), it is noteasy to orientate a guidewire in a sufficiently precise manner aroundthe entire valve because there is the risk of remaining entangled in thechordae tendineae. Indeed, using two guidewires allows to leverage thegeometry of the heart and the natural blood flow to facilitate theoperations and to minimize the risk of errors which can have seriousconsequences for the patient if not identified and correctedimmediately.

Now with reference to FIG. 12 , the first catheter 40 and the secondcatheter 44 are preferably left in position in this step in order tofacilitate the insertion into the ventricle of the two arcs 22 whichconstitute the containment portion 18 of the heart prosthesis 10. Thetwo arcs are inserted over the wire, that is to say by sliding on theguidewires. In other words, there is used a longitudinal channel whichextends through one of the two arcs in order to insert therein the end57 of the guidewire 56 which has just been recovered; similarly, the endof the guidewire 58 is inserted into the longitudinal channel whichextends through the other arc. Both the arcs 22 are then pushed untilthey are out of the first catheter 40 and inside the heart. The arcs 22are pushed until being in contact with the tip 51 of the second catheter44. At this point, the first catheter 40 and the second catheter 44 canbe removed.

It is preferable to leave the main catheter 32 in position and to use itfor subsequently introducing therein a device 60 for implanting a heartprosthesis, in which a central body 16 is inserted. The removal of themain catheter 32 or the replacement thereof with another catheter is notexcluded in any case.

The device 60 for implanting a heart prosthesis, the details of whichcan be seen in FIGS. 13, 14 and 15 , comprises a catheter 61, throughwhich there are inserted all the other elements as well as the centralbody 16 of the prosthesis.

The device for implanting a heart prosthesis further comprises a releasedevice 62 for the central body 16 of the prosthesis. The release device62 is suitable for being inserted into a catheter in order to advancetherein the central body 16 of the prosthesis. The device 60 forimplanting a heart prosthesis further comprises a device 64 forassisting the connection operation between the central body 16 and thesub-components of the containment portion 18. This assistance device 64comprises an assembly of catheters 66, of which there are at least twofor each arc of the containment portion that are grouped together in thesame sheath 68 which partially covers the catheters and leaves at leastone free end 70 for each catheter.

In the preferred case depicted, in which the prosthesis comprises twoarcs 22, the assistance device 64 comprises four catheters 66.Naturally, if the prosthesis were to comprise a single sub-component ofthe containment portion 18, two catheters would be sufficient. If,however, the prosthesis comprises three or more sub-components, six ormore catheters will be provided.

The catheters 66 are incompressible in the longitudinal direction andare flexible. Furthermore, they are fixed inside the sheath 68 so thatthey do not slide with respect to each other. Preferably, the sheath 68further comprises a free longitudinal lumen 72 in which a guidewire canslide if it is advantageous.

Turning now to the implantation procedure for the heart prosthesis 10,for each arc 22 of the containment portion 18 there are inserted the twoends of the guidewire 56, 58 which extend through them, in acorresponding pin 28 of the two connecting elements 20 and then in thecatheters 66 of the assistance device 64. For example, the guidewire 56runs through, in order, a first catheter 66, a first pin 28 of a firstconnecting element 20, an arc 22, a first pin 28 of the other connectingelement 20 and a second catheter 66, as can be seen in FIG. 13 .

The catheter 61 is then forced to advance inside the main catheter 32and through the mitral valve until the end 63 thereof is inside the leftventricle. Although, for greater clarity, FIGS. 16 to 19 show only thedevices, the operations shown therein are normally carried out insidethe heart of the patient.

The central body 16 is then pushed so that it advances further insidethe catheter 61 until the connecting elements 20 are released from thecatheter. It may be noted that, when the central body 16 is in acollapsed configuration, in order to be able to slide inside thecatheter, the connecting elements are deformed. However, they areconstructed from a shape-memory material so that, once they are out ofthe catheter, they immediately take up the intended configuration.

In order to join the central body 16 and the containment portion 18, orin other words to engage the arcs 22 with the connecting elements 20, itis now enough to pull the ends of each guidewire (FIG. 17 ). In thismanner, the pins 28 of the connecting elements 20 are inserted into theaxial holes 27 of the engagement portions 26 which are positioned at theends of the arcs 22. It may be noted that, for tightening, the presenceof the assistance device 64 is of primary importance, and in particularof the catheters 66. In fact, the incompressible catheters 66 allow theguidewires to be pulled without kinking against the edge of the catheter61. In other words, the catheters allow a transfer of a traction force,which otherwise could not be applied, to the portion of guidewire insideeach arc which is sufficient to connect to each other the arcs 22 andthe connecting elements 20.

Once the components of the prosthesis are secured to each other, theguidewires can be retrieved as well as the assistance device 64 (FIG. 18).

Thus, the prosthesis is assembled and maintained in the correct positionwith the central body 16 still inside the catheter 61 and the two arcs22 correctly orientated relative to each other so as to constitute thecontainment portion 18 of the prosthesis (FIGS. 19 and 20 ).

By acting on the release device 62 and on the catheter 61, the centralbody 16 of the prosthesis is forced to advance inside the catheter 61while at the same time the catheter 61 is withdrawn. The central body ismaintained substantially in a stable position inside the heart so thatthe containment portion 18 does not lose contact with the annulus of thenative valve while the catheter 61 is retrieved. The central body 16,when it is released from the catheter 61, expands inside the nativevalve until it is constrained by the containment portion 18 (FIG. 21 ).The leaflets of the native valve thus remain captured between thecentral body of the heart prosthesis and the containment portion 18.This configuration brings about a stable and secure positioning of theprosthesis.

All that has been described above must naturally be understood to be onepossible embodiment of the invention but not the only one. In anexemplary manner, there will now be described some variants of theobjects described above. It should nevertheless be understood that thisis not an exhaustive listing of the possible variants.

According to a variant of the invention, a second catheter 244 and athird catheter 245, visible in cross-section in FIG. 22 , slide insidethe first catheter 40 of the guidewire introducer device 36. The secondcatheter 244 provides two lumens 46 and 48, suitable for havingguidewires sliding therein. The catheter 244, unlike the second catheter44 described above, has a D-shaped cross-section. Preferably, the secondcatheter 244 provides an additional lumen 250 for the passage of thewire 52 of the deflection system of the distal portion of the catheter.

The third catheter 254 also has two lumens 45 a, 45 b, suitable foraccommodating two guidewire capturing devices 47. The third catheter 245also has a D-shaped cross-section which complements the cross-section ofthe second catheter 244. In this manner, the correct mutual orientationbetween the catheter 244 and the catheter 245 is ensured, and thereforebetween the guidewires which are inserted in the lumens 46 and 48 andthe guidewire capturing devices 47. Easier positioning of the guidewiresaround the annulus is thereby allowed.

In this regard, it is evident that the D shape is intended to beunderstood to be exemplary: it is sufficient for the cross-sections ofthe two catheters 244 and 245 to be such as to ensure the retention ofthe correct mutual orientation. For example, the cross-sections of thetwo catheters 244 and 245 are mutually complementary inside the catheter40 (in other words, the two cross-sections juxtaposed correspond to thecross-section of the first catheter 40 of the guidewire introducerdevice 36) and the two catheters 244 and 245 comprise at least oneplanar abutment face 270 and 272, respectively. It will be understoodthat the catheters 244 and 245 can slide independently inside the firstcatheter 40. It is further possible to provide a single lumen 45 a.

The third catheter 245 further has an additional lumen 260 for thepassage of a wire of a deflection system of the distal portion of thecatheter.

With reference now to FIGS. 23 to 26 , a second catheter 344 and a thirdcatheter 345 may comprise mechanically bendable metal structures. Thesemetal structures constitute the lumens 346 and 348 of the secondcatheter 344 and the lumens 345 a, 345 b of the third catheter 345. Eachlumen 346 and 348 has a wire 352 which allows it to be bent. Preferably,each lumen 346 and 348 may form two curves. A first curve is greaterthan 90°, preferably between 120° and 180°; a second curve isapproximately 90°. Preferably, the two curves lay in two mutuallyperpendicular planes. The two curves are obtained by means of respectiveportions 354 and 356 which are suitably perforated in order to createanisotropic sections which advantageously ensure a precise andunambiguous orientation of the lumens. This variant further allowsstraightening of all the lumens before removal of the second and thirdcatheters. In this manner, the friction is greatly reduced, both inrelation to the catheter 40, in which the catheters 344 and 345 slide,and in relation to the guidewires which slide therein, making it easierand faster to withdraw the second and third catheters. Furthermore, themetal lumens have a thickness which is particularly small.

The catheters 344 and 345 slide inside the catheter 40 in a straightenedconfiguration (FIG. 24 ). When they are externalized from the catheter40, the deflection is then activated so as to curve the portions 354 andto produce the first curves (FIG. 25 ). The distal deflection of theportions 356 is then activated in order to produce the second curves(FIG. 26 ). In a generally similar manner, the deflection on the lumens345 a and 345 b of the third catheter is also activated. At the end ofthe operations for positioning the guidewires, all the lumens arestraightened (FIG. 24 ) for the extraction thereof.

Naturally, the principle of the invention remaining the same, the formsof embodiment and details of construction may be varied widely withrespect to those described and illustrated, without thereby departingfrom the scope of the invention.

1. A connection device for connecting a first component and a secondcomponent of a heart prosthesis, said connection device comprising anassembly of at least one pair of catheters, each of the catheters beingincompressible in the longitudinal direction, each of the pair ofcatheters being joined to each other over a portion thereof and eachhaving at least one free end, wherein each of the pair of catheters hasa guidewire inserted in both catheters of each pair of catheters.
 2. Theconnection device according to claim 1, wherein the assembly of at leastone pair of catheters comprises at least two pairs of catheters.
 3. Theconnection device according to claim 2, wherein the catheters areflexible.
 4. The connection device according to claim 3, wherein thecatheters of the assembly of at least one pair of catheters are groupedtogether in a same sheath which groups together the catheters along aportion thereof.
 5. The connection device according to claim 2, whereinthe catheters of the assembly of at least one pair of catheters aregrouped together in a same sheath which groups together the cathetersalong a portion thereof.
 6. The connection device according to claim 1,wherein the catheters are flexible.
 7. The connection device accordingto claim 6, wherein the catheters of the assembly of at least one pairof catheters are grouped together in a same sheath which groups togetherthe catheters along a portion thereof.
 8. The connection deviceaccording to claim 1, wherein the catheters of the assembly of cathetersare grouped together in a same sheath which groups together thecatheters along a portion thereof.